IC封装导电银胶用片状银粉的研制

先通过液相化学还原法制备原始银粉,再利用机械球磨法制得片状银粉,对银粉的形貌、粒度分布、粉体密度、比表面积、水分灰分进行表征,研究原始粉制备工艺、球磨工艺对片状银粉形貌尺寸、粒度分布及密度的影响。结果表明,以分散性好及平均粒径约3μm的球形银粉为原始银粉、无水乙醇为介质,2 mm尺寸规格的氧化锆球为磨球,球磨时间为35 h,机械球磨法制得片状化程度高、粒径均匀、平均粒径小于7μm的片状银粉。将片状银粉用环氧树脂体系配制成IC封装导电银胶,测试导电胶固化前的物性参数、固化片的特性、固化粘接特性及环境测试,并常温下观察是否分层,均达到了应用指标要求。

Preparation of Flake Silver Powder for IC Package Conductive Silver Adhesive

A combined preparing method of flack silver powder is introduced,in which the original silver powder is prepared by chemical reduction in liquid phase,and then flake silver powder by mechanical ball-milling.The morphology,particle size distribution,powder density,specific surface area,moisture and ash content of the silver powder are characterized.The effects of original powder preparation technology and ball-milling process on morphology,size distribution and density of flake silver powder are studied.The results show that the flake silver powder with high degree of flake,uniform particle size and average particle size less than 7μm can be obtained by mechanical ball-milling with spherical silver powder with good dispersion and average particle size of about 3μm as the original silver powder,anhydrous ethanol as the medium and zirconia ball with the size of 2 mm as the grinding ball for 35 h ball milling.For the conductive silver adhesive for IC packaging prepared from flake silver powder with epoxy resin system,the physical parameters,curing and bonding properties of the conductive adhesive before curing,curing and bonding properties,and environmental testing,and the stratification observing at room temperature are introduced in detail,which show that all of them meet the application requirements.